• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1471-1478
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• 2011

A typical standard of vehicular ad hoc networks, WAVE which consists of IEEE 1609.x Family standards and IEEE 802.11p standard, includes the multi-channel coordination and channel synchronization function to provide safety services or public services during a car is driven. Generally, the performance of data communication and networking technologies is evaluated by using simulation tools, such as ns-2, OPNET, OPNET++, etc. However, these tools doesn't provide the operations of WAVE protocol. Therefore, in this paper, we implement and verify WAVE simulation program based on ns-2.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.322-331
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• 2013

Wireless Mesh Networks(WMNs) is generally composed of radio nodes in the mesh topology. WMNs consists of mesh client, mesh router and gateway connected to a wired network. Each client and router relay messages to the gateway for communication. WMNs is widely used recently in many areas can provide extended coverage based on multi-hop communication and ubiquitous communication at any time and any location. However the competition and collision between each node to transmit data is inevitable when the same channel is used for transmission. The transmission opportunities and the throughput of nodes located far from gateway decrease more if the communication channel is accessed based on competitive CSMA/CA scheme using DCF(Distributed Coordination Function) provided by IEEE 802.11 MAC. In this paper, we improve the performance of the TCP fairness and throughput of the nodes with more than 2 hops by applying various algorithms for controlling contention window values. Also, we evaluate the performance using ns-2 simulator, According to the results, proposed scheme can enhance the fairness characteristic of each node irrespective of data to the gateway.